Surface bonding in halogenated polymeric components

ABSTRACT

Etching the surface (activating the surface) of a halogenated polymer component with an electron beam generates a set of free radical sites in polymeric chains of the surface that sustain for at least 4 hours in an inert environment. The inert environment is provided by a noble gas, nitrogen, a static free space, and/or a vacuum. Items such as dynamic seals, static seals, gaskets, pump diaphragms, hoses, and o-rings all benefit from precursors made according to the technique.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.10/881,129 filed on Jun. 30, 2004, the disclosure of which isincorporated herein by reference.

INTRODUCTION

This invention relates to articles formed from at least one halogenatedpolymer component having an activated surface. In particular, thepresent invention relates to activating halogenated polymer componentsurfaces with radiation.

Composites are important materials in enabling many of the benefits ofmodern life. Composites provide multilayered structures havingindividual layers made of metal, polymer, or ceramic. Each layercontributes to the overall performance of the composite as viewed fromthe intended application. This is especially true of the outside layersof a composite.

Halogenated polymer layers bring useful performance properties tocomposites. However, halogenated polymer layers are also challenging tobond into composites. What is needed is a way to bond a layer made ofhalogenated polymer to other materials while retaining the desiredproperties of the halogenated polymer layer. This and other needs areachieved with the invention.

SUMMARY

The invention provides a method for etching an article made ofhalogenated polymer, comprising

(a) etching a surface of the article with an electron beam; and

(b) placing the surface in an inert environment at a predeterminedtemperature;

where the electron (bombardment) beam energizes the surface withsufficient energy for dislodging a plurality of halogen atoms from thehalogenated polymer of the surface and for generating thereby a set ofinitial residual free radical sites in polymeric chains of the surfaceupon conclusion of the etching, and the inert environment and thepredetermined temperature are sufficient for sustaining at least 99percent of the free radical sites of the set of initial residual freeradical sites for at least 4 hours.

In one form of the invention, the inert environment is a noble gas. Inone form of this, the inert environment is a noble gas at a pressure ofless than 0.1 atmospheres. In another form of the invention, the inertenvironment is nitrogen. In yet another aspect, a vacuum is applied tothe etched material surface. In yet another aspect, a static freeenvironment as a space free of static is enabled at the etched materialsurface.

In one form of the invention, the electron beam radiation is generatedof from about 0.1 MeRAD to about 40 MeRAD (preferably, from about 5MeRAD to about 20 MeRAD).

In one form of the invention, an etched halogenated polymer precursorcomponent is made for use in making an article such as a dynamic seal, astatic seal, a gasket, a pump diaphragm, a hose, or an o-ring.

Further areas of applicability will become apparent from the detaileddescription provided hereinafter. It should be understood that thedetailed description and specific examples, while indicating embodimentsof the invention, are intended for purposes of illustration only and arenot intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings of FIGS. 1 to 4.

FIG. 1 presents a ternary composition diagram for tetrafluoroethylene(TFE), hexfluoropropylene (HFP), and vinylidene fluoride blends;

FIG. 2 shows a molecular schematic of a bi-modal molecule derived froman elastomer and a thermoplastic;

FIG. 3 overviews a portion of an admixture of elastomer andthermoplastic; and

FIG. 4 presents a general three-layer composite structure.

It should be noted that the figures set forth herein are intended toexemplify the general characteristics of an apparatus, materials, andmethods among those of this invention, for the purpose of thedescription of such embodiments herein. The figures may not preciselyreflect the characteristics of any given embodiment, and are notnecessarily intended to define or limit specific embodiments within thescope of this invention.

DESCRIPTION

The following definitions and non-limiting guidelines must be consideredin reviewing the description of this invention set forth herein.

The headings (such as “Introduction” and “Summary”) used herein areintended only for general organization of topics within the disclosureof the invention, and are not intended to limit the disclosure of theinvention or any aspect thereof. In particular, subject matter disclosedin the “Introduction” may include aspects of technology within the scopeof the invention, and may not constitute a recitation of prior art.Subject matter disclosed in the “Summary” is not an exhaustive orcomplete disclosure of the entire scope of the invention or anyembodiments thereof.

The citation of references herein does not constitute an admission thatthose references are prior art or have any relevance to thepatentability of the invention disclosed herein. All references cited inthe Description section of this specification are hereby incorporated byreference in their entirety.

The description and specific examples, while indicating embodiments ofthe invention, are intended for purposes of illustration only and arenot intended to limit the scope of the invention. Moreover, recitationof multiple embodiments having stated features is not intended toexclude other embodiments having additional features, or otherembodiments incorporating different combinations the stated of features.

As used herein, the words “preferred” and “preferably” refer toembodiments of the invention that afford certain benefits, under certaincircumstances. However, other embodiments may also be preferred, underthe same or other circumstances. Furthermore, the recitation of one ormore preferred embodiments does not imply that other embodiments are notuseful, and is not intended to exclude other embodiments from the scopeof the invention.

As used herein, the word “include,” and its variants, is intended to benon-limiting, such that recitation of items in a list is not to theexclusion of other like items that may also be useful in the materials,compositions, devices, and methods of this invention.

Most items of manufacture represent an intersection of considerations inboth mechanical design and in materials design. In this regard,improvements in materials frequently are intertwined with improvementsin mechanical design. The embodiments describe compounds, compositions,assemblies, and manufactured items that enable improvements inirradiation-augmented polymer material synthesis to be fully exploited.

The examples and other embodiments described herein are exemplary andnot intended to be limiting in describing the full scope of compositionsand methods of this invention. Equivalent changes, modifications andvariations of specific embodiments, materials, compositions and methodsmay be made within the scope of the present invention, withsubstantially similar results.

The embodiments relate to synthetic polymer chains (especially materialshaving a halogenated polymer phase or portion) from a process initiatedwith free radical formation derived from irradiation (especiallyelectron beam radiation) of an element (preferably a halogen element)connected to a polymer chain.

Carbon-chain-based polymeric materials (polymers) are usefully definedas falling into one of three traditionally separate generic primarycategories: thermoset materials (one type of plastic), thermoplasticmaterials (a second type of plastic), and elastomeric (or rubber-like)materials (elastomeric materials are not generally referenced as being“plastic” insofar as elastomers do not provide the property of a solid“finished” state). An important measurable consideration with respect tothese three categories is the concept of a melting point—a point where asolid phase and a liquid phase of a material co-exist. In this regard, athermoset material essentially cannot be melted after having been “set”or “cured” or “cross-linked”. Precursor component(s) to the thermosetplastic material are usually shaped in molten (or essentially liquid)form, but, once the setting process has executed, a melting pointessentially does not exist for the material. A thermoplastic plasticmaterial, in contrast, hardens into solid form (with attendant crystalgeneration), retains its melting point essentially indefinitely, andre-melts (albeit in some cases with a certain amount of degradation ingeneral polymeric quality) after having been formed. An elastomeric (orrubber-like) material does not have a melting point; rather, theelastomer has a glass transition temperature where the polymericmaterial demonstrates an ability to usefully flow, but withoutco-existence of a solid phase and a liquid phase at a melting point.

Elastomers are frequently transformed into very robust flexiblematerials through the process of vulcanization. Depending upon thedegree of vulcanization, the glass transition temperature may increaseto a value that is too high for any practical attempt at liquefaction ofthe vulcanizate. Vulcanization implements inter-bonding betweenelastomer chains to provide an elastomeric material more robust againstdeformation than a material made from the elastomers in theirpre-vulcanized state. In this regard, a measure of performance denotedas a “compression set value” is useful in measuring the degree ofvulcanization (“curing”, “cross-linking”) in the elastomeric material.For the initial elastomer, when the material is in non-vulcanizedelastomeric form, a non-vulcanized compression set value is measuredaccording to ASTM D395 Method B and establishes thereby an initialcompressive value for the particular elastomer. Under extendedvulcanization, the elastomer vulcanizes to a point where its compressionset value achieves an essentially constant maximum respective to furthervulcanization, and, in so doing, thereby defines a material where afully vulcanized compression set value for the particular elastomer ismeasurable. In applications, the elastomer is vulcanized to acompression set value useful for the application.

Augmenting the above-mentioned three general primary categories ofthermoset plastic materials, thermoplastic plastic materials, andelastomeric materials are two blended combinations of thermoplastic andelastomers (vulcanizates) generally known as TPEs and TPVs.Thermoplastic elastomer (TPE) and thermoplastic vulcanizate (TPV)materials have been developed to partially combine the desiredproperties of thermoplastics with the desired properties of elastomers.As such, TPE and TPV materials are usually multi-phase admixtures ofelastomer (vulcanizate) in thermoplastic. Traditionally, the elastomer(vulcanizate) phase and thermoplastic plastic phase co-exist in phaseadmixture after solidification of the thermoplastic phase; and theadmixture is liquefied by heating the admixture above the melting pointof the thermoplastic phase of the TPE or TPV.

Another form of modification to the traditional three general primarycategories of thermoset plastic materials, thermoplastic plasticmaterials, and elastomeric materials is cross-linked thermoplasticmaterial, where a thermoplastic undergoes a certain degree ofcross-linking via a treatment such as irradiation after having beensolidified (to contain crystals of the thermoplastic polymer). In thisregard, while the melting point of crystals in a cross-linkedthermoplastic is sustained in all crystalline portions of thethermoplastic, the dynamic modulus of the cross-linked thermoplasticwill be higher than that of the non-crosslinked thermoplastic due tocrosslinkage between thermoplastic molecules in the amorphous phase ofthe thermoplastic.

Some embodiments of this specification derive from the inter-linking ofmolecules of an elastomer or vulcanizate with molecules of athermoplastic. In this regard, a new type of compound is formed: amolecule (usually a macromolecule) having one moiety (significantportion or significant sub-molecular part of a molecule) derived from anelastomer or vulcanizate and a second moiety derived from a plastic. Insome embodiments, the plastic moiety is derived from thermoplasticplastic; in other embodiments, the plastic is derived from thermosetplastic.

Some further embodiments of this specification derive from theinter-linking of molecules of an elastomer or vulcanizate with moleculesof a ceramic compound. In this regard, a new type of compound is formed:a molecule (usually a macromolecule) having one moiety (significantportion or significant sub-molecular part of a molecule) derived from anelastomer or vulcanizate and a second moiety derived from a ceramiccompound.

Other embodiments of this specification derive from the inter-linking ofmolecules of an elastomer or vulcanizate with a metal element. In thisregard, a molecule (usually a macromolecule) having a metal elementbonded to an elastomer or vulcanizate provides a new form of elastomer.In this regard, it is to be noted that a traditional practice of bondingan elastomer or vulcanizate to a metal employs a silane-derived group toconjoin a metallic silane to the elastomer with hydrogen bonds or vander Waals forces.

In one embodiment, the elastomeric moiety is generated from bombardingan elastomeric molecule with a beam of energy that is sufficientlysignificant to dislodge an element (preferably a halogen element such asfluorine) from the carbon chain of the elastomer but sufficientlymitigated to avoid breaking or severing of the chain. After the element(halogen or other element) is dislodged, a free radical derivative ofthe original elastomeric molecule exists with a free radical site on theelement (usually carbon) in the polymer chain to which the dislodgedelement (the halogen, usually) was previously bonded. Whilefree-radicals usually react very rapidly with other materials (indeed,they are frequently referenced as very short-term intermediary entitiesin kinetic models describing rapidly-executed multistage chemicalreactions), a free radical polymer chain appears to be surprisinglystable in the free radical state, especially if the polymeric freeradical is constrained from movement and also constrained from contactwith other materials that would bond to the free radical site of thepolymer chain. Indeed, the stability of such free radical sites onpolymer chains is surprising when a halogenated polymer is irradiatedwith electron beam radiation to energize a halogen element on thepolymer with energy sufficient to remove that halogen from the polymerand thereby generate a free radical site on the polymer chain. Apreferred method of generating the free radical site(s) is with anelectron beam.

It is known that modifications in polymeric structures are effected byradiation. The radiation is alternatively radioactively sourced, lasersourced, or sourced by an electron accelerator. After irradiation of thepolymer molecules, the polymer chains are modified to include danglingbonds between the atoms of the polymer chains or to have broken, bent,or strained chains. Irradiative treatment can also generate either freeradicals or high-energy chemical bonds in molecules of admixed polymers.These bonds include covalent and ionic bonds as well as those otherbonds created by electronic or electrostatic attraction (for example,Van der Waal's forces). And it has been shown that another polymericitem may be bonded to the irradiated polymeric structure without furtheruse of adhesives.

In a preferred embodiment, the above considerations are the basis for anapproach that first generates free radical or reduced sites (in thecontext of “reduction” meaning the loss of an electron, a reduced siteis a site having an electron deficient shell state on any element in thepolymeric chain—the “chain element”—where the site is generated byremoving an electron from the “chain” element to, in essence, “reduce”that “chain” element to a higher energy state respective to the residualunpaired electron still remaining in orbital association with the“chain” element after the removal of the electron with which theremaining electron was paired) on both an elastomer and also in a secondmaterial. In this regard, it should be noted that the “chain” element(possessing the free radical site) lost the electron that reduced thesite when that electron departed from the polymeric chain with the“removed” element that was energized to the point where it separatedfrom the “chain” element. The second material may be a metal, a ceramiccompound, or a thermoplastic polymer. The two free radicals (or freeradical elastomer derivative and “reduced” metal element) are thenpositioned (or retained in a position usefully appropriate by virtue oftheir positioning prior to irradiation) and further energized as neededso that (a) the free radical elastomer molecule (derived from theelastomer) and (b) the respective second free-radical or reduced bondsite of any of the free radical ceramic molecule, free radicalthermoplastic molecule, or reduced metal element bond together at theirrespective high energy electron sites (free radical sites or reducedsites) to yield a new molecule having one moiety derived from the freeradical elastomer and a second moiety from the selected non-elastomer(such as any of the free radical thermoplastic molecule, the freeradical ceramic compound, or the reduced metal element). As should alsobe appreciated, the amount of energy is also controlled to minimizedestruction of the polymeric chains upon which free radical sites arebeing generated. In this regard, it is efficacious in the new moleculesof the embodiments for the free radical sites to be at interim locationson the polymer chains rather than at endpoints where the initial polymerchains were severed or broken by the radiation.

With respect to the bonding, the size of the free-radical molecules(molecular weight of from about 350 to about 10,000,000 for the freeradical elastomer molecule, and from about 120 to about 10,000,000 for afree radical thermoplastic molecule when the non-elastomer is athermoplastic molecule) is also desired for providing optimal mobilityof the free-radicals (the polymeric chains with a free radical site) toultimately bond at their respective high energy electron sites andthereby create the new molecules of the embodiments.

The radiation is absorbed by an element (a first element) on theelastomer, and that (first) element is boosted to an energy levelwhereby it detaches from the general elastomer molecule. As notedbefore, this leaves another (second) element in the polymer chain (wherethe second element was previously attached to the first element) with afree radical site. The amount of energy absorbed (the dose) is measuredin units of kiloGays (kGy), where 1 kGy is equal to 1,000 Joules perkilogram, or MegaRads (MR, MeRAD, or Mrad), where 1 MR is equal to1,000,000 ergs per gram.

Electron beam processing is usually effected with an electronaccelerator. Individual accelerators are usefully characterized by theirenergy, power, and type. Low-energy accelerators provide beam energiesfrom about 150 keV to about 2.0 MeV. Medium-energy accelerators providebeam energies from about 2.5 to about 8.0 MeV. High-energy acceleratorsprovide beam energies greater than about 9.0 MeV. Accelerator power is aproduct of electron energy and beam current. Such powers range fromabout 5 to about 300 kW. The main types of accelerators are:electrostatic direct-current (DC), electrodynamic DC, radiofrequency(RF) linear accelerators (LINACS), magnetic-induction LINACs, andcontinuous-wave (CW) machines.

In one embodiment, the particular combination of an elastomer(alternatively, a vulcanizate) with any of a metallic element, aceramic, and a polymeric carbon chain thermoplastic by use ofradiation-facilitated bonding appears to create a new compound when theelastomer molecule is treated with radiation such as an electron beam.This compound corresponds to the Formula I:ADwhere A is a polymeric carbon chain elastomeric moiety containingelastomeric functionality and having a collective atomic weight of fromabout 350 to about 10,000,000, and D is any of a metallic element, aceramic moiety, and a polymeric carbon chain thermoplastic moiety. Inthe case of D being a polymeric carbon chain thermoplastic moiety, D isa free radical polymeric derivative of a thermoplastic molecule having amolecular weight of from about 120 to about 10,000,000. In the case of Dbeing a ceramic moiety, D is a free radical ceramic compound derivativeof a ceramic compound. In either of the cases, where D is a polymericcarbon chain thermoplastic moiety or a ceramic moiety, electron-beamtreatment of the precursor respective thermoplastic molecule or ceramiccompound is the preferred manner for making the respective free radicalderivatives.

The A moiety is derived from a free radical polymeric derivative of anelastomer molecule. In alternative embodiments, this elastomer moleculeis any of a fluoroelastomer molecule, an acrylic acid esterrubber/polyacrylate rubber molecule, an ethylene acrylic rubbermolecule, a silicone molecule, a nitrile butyl rubber molecule, ahydrogenated nitrile rubber molecule, or a polyurethane molecule.

In the case of D being a polymeric carbon chain thermoplastic moiety, Dis derived from a free radical polymeric derivative of an thermoplasticmolecule. In alternative embodiments, this thermoplastic molecule is anyof a polyamide molecule, a nylon 6 molecule, a nylon 66 molecule, anylon 64 molecule, a nylon 63 molecule, a nylon 610 molecule, a nylon612 molecule, an amorphous nylon molecule, a polyester molecule, apolyethylene terephthalate molecule, a polystyrene molecule, apolymethyl methacrylate molecule, a thermoplastic polyurethane molecule,a polybutylene molecule, a polyesteretherketone molecule, a polyimidemolecule, a fluoroplastic molecule, a polyvinylidene fluoride molecule,a polysulfone molecule, a polycarbonate molecule, a polyphenylenesulfide molecule, a polyethylene molecule, a polypropylene molecule, apolyacetal molecule, a perfluoroalkoxy(tetrafluoroethylene/perfluoromethylvinyl ether) molecule, atetrafluoroethylene/perfluoromethylvinyl ether molecule, an ethylenetetrafluoroethylene molecule, an ethylene chlorotrifluoroethylenemolecule, a tetrafluoroethylene/hexafluoropropylene/vinylidene fluoridemolecule, a tetrafluoroethylene/hexafluoropropylene molecule, apolyester thermoplastic ester molecule, a polyester ether copolymermolecule, a polyamide ether copolymer molecule, and a polyamidethermoplastic ester molecule.

Turning now to FIG. 1, a ternary composition diagram 100 is presentedshowing tetrafluoroethylene (TFE), hexfluoropropylene (HFP), andvinylidene fluoride weight percentage combinations for making variousco-polymer blends. Region 101 defines blends of respectivetetrafluoroethyl, hexfluoropropyl, and vinylidyl fluoride overall blockamounts that combine to form fluoroelastomer (FKM) polymers. Region 104defines blends of respective tetrafluoroethyl, hexfluoropropyl, andvinylidyl fluoride overall block amounts that combine to formperfluoroalkoxy tetrafluoroethylene/perfluoromethylvinyl ether andtetrafluoroethylene/hexafluoropropylene polymers. Region 106 definesblends of respective tetrafluoroethyl, hexfluoropropyl, and vinylidylfluoride overall block amounts that combine to formtetrafluoroethylene/hexafluoropropylene/vinylidene fluoride polymers.Region 108 defines blends of respective tetrafluoroethyl,hexfluoropropyl, and vinylidyl fluoride overall block amounts thatcombine to form ethylene tetrafluoroethylene polymers. Region 110defines blends of respective tetrafluoroethyl, hexfluoropropyl, andvinylidyl fluoride overall block amounts that traditionally have notgenerated useful co-polymers. Region 102 defines blends of respectivetetrafluoroethyl, hexfluoropropyl, and vinylidyl fluoride overall blockamounts that combine to form polytetrafluoroethylene (PTFE) polymers.Region 114 defines blends of respective tetrafluoroethyl,hexfluoropropyl, and vinylidyl fluoride overall block amounts thatcombine to form polyvinylidene fluoride (PVdF) polymers. Region 116defines blends of respective tetrafluoroethyl, hexfluoropropyl, andvinylidyl fluoride overall block amounts that combine to formpolyhexfluoropropylene (PHFP) polymers.

Returning to a consideration of the compound of Formula I, theembodiment of Formula I provides, in one perspective, a molecularchimera (bi-modal molecule) where one portion is elastomeric in itsfundamental nature and a second portion is a non-elastomeric in itsfundamental nature. A molecule of this structure therefore provides achemical structure having one portion that is structurally conformantwith an elastomer and a second portion that is structurally conformantwith a non-elastomer. Accordingly, the general bonding between anelastomeric region and a non-elastomeric region is potentially very highwhen such molecules exist as inter-bonding molecules at the interfacebetween the two regions. Such bonding between regions with inter-bondingmolecules (such as the compound of Formula I) is superior to region toregion bonding derived from electronic or electrostatic attraction (forexample, Van der Waal's forces) between molecules of the two regions,even when those forces derive from free radicals or reduced elementsthat were prepared by use of radiation.

In preferred embodiments of the compound of Formula I, D is halogenatedplastic and A is from a molecule corresponding to the Formula II:[-TFE_(q)-HFP_(r)-VdF_(s)-]_(d)where TFE is essentially a tetrafluoroethyl block, HFP is essentially ahexfluoropropyl block, and VdF is essentially a vinylidyl fluorideblock, and products qd and rd and sd collectively provide proportions ofTFE, HFP, and VdF whose values are within Region 101 (drawing element101) of FIG. 1.

One embodiment of the molecule (compound) according to Formula I ispartially depicted by molecular schematic 200 in FIG. 2, where moiety A(moiety 202—where products qd and rd and sd collectively provideproportions of TFE, HFP, and VdF whose values are within Region 101 ofFIG. 1 and where qd, rd, and sd taken together provide a collectiveatomic weight of about 750,000 for moiety 202), is attached withcovalent bond to moiety D (moiety 204-—where products mp and np and optogether provide a collective atomic weight of about 750,000 for moiety204). Moiety 202 is derived from a fluoroelastomer. Moiety 204 isderived from a halogenated thermoplastic. Accordingly, Z is(independently within any of the sub-blocks replicated in any of therespective m instances, n instances, and o instances) any of F, Cl, I,Br, H, or a functional group; and X is (independently within any of thesub-blocks replicated in any of the respective m instances, n instances,and o instances) any of F, Cl, I, or Br. In this regard, halogenatedpolymers demonstrate especially good free radical generation throughremoval of a halogen from their carbon chains when subjected to electronbeam radiation (preferably with electron beam radiation of from about0.1 MeRAD to about 40 MeRAD and, more preferably, with electron beamradiation of from about 5 MeRAD to about 20 MeRAD). Bond 206 isestablished from the locations where the original elastomer molecule andthe original halogenated thermoplastic molecule “lost” halogens toprovide subsequent free radical sites prior to the establishment of bond206.

As previously noted, the general bonding between an elastomeric regionand a non-elastomeric region is potentially very high when moleculesaccording to Formula I exist as inter-bonding molecules at the interfacebetween the two regions. Several alternative embodiments of materials,compositions, and articles having such diverse regions benefit fromthese inter-bonding molecules.

One embodiment of a diverse region material having a continuous phaseand a dispersed phase is admixture 300 as shown in FIG. 3. Admixture 300is a polymeric blend (admixture) of an elastomer (alternatively,vulcanizate) phase and a plastic phase, where the plastic phase isinitially admixed as a thermoplastic. After admixing, admixture 300, is,irradiated (preferably with electron beam radiation) to cross-link thethermoplastic and further vulcanize or otherwise modify the elastomer(or vulcanizate).

An admixture, such as admixture 300, established by admixing phases ofpolymer usually differentiates the continuous phase and dispersed phaseon the basis of relative viscosity between two initial polymeric fluids(where the first polymeric fluid has a first viscosity and the secondpolymeric fluid has a second viscosity). The phases are differentiatedduring admixing of the admixture from the two initial polymeric fluids.In this regard, the phase having the lower viscosity of the two phaseswill generally encapsulate the phase having the higher viscosity. Thelower viscosity phase will therefore usually become the continuous phasein the admixture, and the higher viscosity phase will become thedispersed phase. When the viscosities are essentially equal, the twophases will form an interpenetrated structure of polymer chains.Accordingly, in general dependence upon the relative viscosities of theadmixed elastomer and thermoplastic, several embodiments of admixedcompositions derive from the general admixing approach and irradiation.

In a first admixture embodiment, admixture 300 has a continuous phase ofcross-linked plastic 302 cross-linked from prior thermoplastic polymer.Admixture 300 also has a dispersed phase of vulcanized elastomer in aplurality of vulcanized elastomeric portions (such as portion 304)dispersed in continuous phase 302. Admixture 300 in this embodiment istherefore derived from intermixing relatively high viscosity elastomer(or partially vulcanized elastomer) with relatively low viscositythermoplastic and then irradiating (preferably with electron beamradiation) the admixture. In one embodiment of admixture 300, vulcanizedelastomer portions are vulcanized to provide a compression set valuefrom about 50 to about 100 percent of the difference between anon-vulcanized compression set value respective to the base elastomerand a fully-vulcanized compression set value respective to the baseelastomer.

In this regard, it is to be noted that percentage in the 50 to about 100percent range respective to the difference (between a non-vulcanizedcompression set value respective to the base elastomer and afully-vulcanized compression set value respective to the base elastomer)applies to the degree of vulcanization in the elastomer rather than topercentage recovery in a determination of a particular compression setvalue. As an example, an elastomer prior to vulcanization has anon-vulcanized compression set value of 72 (which could involve a 1000%recovery from a thickness measurement under compression to a thicknessmeasurement after compression is released). After extendedvulcanization, the vulcanized elastomer demonstrates a fully-vulcanizedcompression set value of 10. The difference between the values of 72 and10 indicate a range of 62 between the non-vulcanized compression setvalue respective to the base elastomer and a fully-vulcanizedcompression set value respective to the base elastomer. Since thecompression set value decreased with vulcanization in the example, acompressive set value within the range of 50 to about 100 percent of thedifference between a non-vulcanized compression set value respective tothe base elastomer and a fully-vulcanized compression set valuerespective to the base elastomer would therefore be achieved with acompressive set value between about 41 (50% between 72 and 10) and about10 (the fully-vulcanized compression set value).

Continuous phase 302 and the dispersed phase (such as portion 304) areinter-bonded by (at least one) inter-bonding molecule(s) correspondingto an elastomer-thermoplastic polymer according to Formula I; theseinter-bonding molecules strengthen regional interfaces such as interface306. The A moiety of the Formula I compound is derived from a moleculeof the initial elastomer phase (as admixed prior to irradiationtreatment), and the D moiety is derived from a molecule of the initialthermoplastic phase (as admixed prior to irradiation treatment).

In preferred embodiments of admixture 300, vulcanized elastomer isderived from any of the elastomers of fluoroelastomer, acrylic acidester rubber/polyacrylate rubber, ethylene acrylic rubber, silicone,nitrile butyl rubber, hydrogenated nitrile rubber, polyurethane, andcombinations thereof. The cross-linked thermoplastic polymer iscross-linked from any of the thermoplastics of polyamide, nylon 6, nylon66, nylon 64, nylon 63, nylon 610, nylon 612, amorphous nylon,polyester, polyethylene terephthalate, polystyrene, polymethylmethacrylate, thermoplastic polyurethane, polybutylene,polyesteretherketone, polyimide, fluoroplastic, polyvinylidene fluoride,polysulfone, polycarbonate, polyphenylene sulfide, polyethylene,polypropylene, polyacetal polymer, polyacetal, perfluoroalkoxy(tetrafluoroethylene/perfluoromethylvinyl ether),tetrafluoroethylene/perfluoromethylvinyl ether, ethylenetetrafluoroethylene, ethylene chlorotrifluoroethylene,tetrafluoroethylene/hexafluoropropylene/vinylidene fluoride,tetrafluoroethylene/hexafluoropropylene, polyester thermoplastic ester,polyester ether copolymer, polyamide ether copolymer, polyamidethermoplastic ester, and combinations thereof.

Preferably, each of the vulcanized elastomeric portions (such as portion304) has a cross-sectional diameter from about 0.1 microns to about 100microns. In this regard, it is to be further appreciated that anyportion (such as portion 304) is essentially spherical in shape In oneembodiment, or, in an alternative embodiment, is filamentary (such as inportion 308) in shape with the filament having a cross-sectionaldiameter from about 0.1 microns to about 100 microns.

The dispersed phase portions (such as portion 304) collectively are fromabout 20 weight percent to about 90 weight percent of the admixture 300composition.

In a second admixture embodiment, admixture 300 has a continuous phaseof vulcanized elastomer 302 cross-linked from initially admixedelastomer (or initially admixed lightly vulcanized elastomer) and isderived from intermixing relatively high viscosity thermoplastic withrelatively low viscosity elastomer (or partially vulcanized elastomer)and then irradiating (preferably with electron beam radiation) theadmixture. Admixture 300 also has a dispersed phase of cross-linkedplastic in a plurality of cross-linked plastic portions (such as portion304) dispersed in continuous phase 302. In one embodiment of admixture300, vulcanized elastomer 302 is vulcanized to provide a compression setvalue from about 50 to about 100 percent of the difference between anon-vulcanized compression set value for the base elastomer and afully-vulcanized compression set value for the base elastomer. Theplurality of cross-linked plastic portions (such as portion 304) asdispersed in continuous phase 302 are cross-linked plastic ascross-linked from thermoplastic polymer.

The continuous phase 302 and dispersed phase (such as portion 304) ofthis second admixture embodiment are inter-bonded by (at least one)inter-bonding molecule(s) corresponding to an elastomer-thermoplasticpolymer according to Formula I; these inter-bonding molecules strengthenregional interfaces such as interface 306. The A moiety of the Formula Icompound is derived from a molecule of the initial elastomer phase (asadmixed prior to irradiation treatment), and the D moiety is derivedfrom a molecule of the initial thermoplastic phase (as admixed prior toirradiation treatment).

In preferred embodiments of this second embodiment of admixture 300,vulcanized elastomer is derived from any of the elastomers offluoroelastomer, acrylic acid ester rubber/polyacrylate rubber, ethyleneacrylic rubber, silicone, nitrile butyl rubber, hydrogenated nitrilerubber, polyurethane, and combinations thereof. The cross-linkedthermoplastic polymer is cross-linked from any of the thermoplastics ofpolyamide, nylon 6, nylon 66, nylon 64, nylon 63, nylon 610, nylon 612,amorphous nylon, polyester, polyethylene terephthalate, polystyrene,polymethyl methacrylate, thermoplastic polyurethane, polybutylene,polyesteretherketone, polyimide, fluoroplastic, polyvinylidene fluoride,polysulfone, polycarbonate, polyphenylene sulfide, polyethylene,polypropylene, polyacetal polymer, polyacetal, perfluoroalkoxy(tetrafluoroethylene/perfluoromethylvinyl ether),tetrafluoroethylene/perfluoro-methylvinyl ether, ethylenetetrafluoroethylene, ethylene chlorotrifluoroethylene,tetrafluoroethylene/hexafluoropropylene/vinylidene fluoride,tetrafluoro-ethylene/hexafluoropropylene, polyester thermoplastic ester,polyester ether copolymer, polyamide ether copolymer, polyamidethermoplastic ester, and combinations thereof.

Preferably, each of the cross-linked plastic portions (such as portion304) has a cross-sectional diameter from about 0.1 microns to about 100microns. In this regard, it is to be further appreciated that anyportion (such as portion 304) is essentially spherical in shape In oneembodiment, or, in an alternative embodiment, is filamentary (such as inportion 308) in shape with the filament having a cross-sectionaldiameter from about 0.1 microns to about 100 microns.

The continuous phase (portion 302) of this second embodimentcollectively is from about 20 weight percent to about 90 weight percentof the admixture 300 composition.

In a third admixture embodiment, an interpenetrated structure admixtureof molecules of an elastomer, molecules of a thermoplastic, and amolecule (alternatively, molecules) corresponding to anelastomer-thermoplastic polymer according to Formula I is (are) derivedfrom intermixing elastomer and thermoplastic materials of essentiallycomparable viscosity and then irradiating (preferably with electron beamradiation) the admixture. Such an interpenetrated structure may also betermed as a “polymeric alloy” or “polymeric alloy blend” respective toexistence of highly interspersed and/or interwoven microphases such asexist in crystalline and non-crystalline phases in metallic alloys.

In preferred embodiments of this third admixture embodiment, elastomeris derived from any of the elastomers of fluoroelastomer, acrylic acidester rubber/polyacrylate rubber, ethylene acrylic rubber, silicone,nitrile butyl rubber, hydrogenated nitrile rubber, polyurethane, andcombinations thereof. The cross-linked thermoplastic polymer iscross-linked from any of the thermoplastics of polyamide, nylon 6, nylon66, nylon 64, nylon 63, nylon 610, nylon 612, amorphous nylon,polyester, polyethylene terephthalate, polystyrene, polymethylmethacrylate, thermoplastic polyurethane, polybutylene,polyesteretherketone, polyimide, fluoroplastic, polyvinylidene fluoride,polysulfone, polycarbonate, polyphenylene sulfide, polyethylene,polypropylene, polyacetal polymer, polyacetal, perfluoroalkoxy(tetrafluoroethylene/perfluoro-methylvinyl ether),tetrafluoroethylene/perfluoromethylvinyl ether, ethylenetetrafluoroethylene, ethylene chlorotrifluoroethylene,tetrafluoroethylene/hexa-fluoropropylene/vinylidene fluoride,tetrafluoroethylene/hexafluoropropylene, polyester thermoplastic ester,polyester ether copolymer, polyamide ether copolymer, polyamidethermoplastic ester, and combinations thereof.

Prior to irradiation, the elastomer of this third embodiment is fromabout 20 weight percent to about 90 weight percent of the polymericadmixture. In this interpenetrated structure embodiment, with somedependence upon the portion of elastomer in the admixture, the yield ofmolecules corresponding to Formula I is, in some embodiments, higherthan in the first and second admixture embodiments.

A composite as generally presented in composite 400 of FIG. 4 providesanother embodiment of a material, composition, and/or article havingdiverse regions benefiting from inter-bonding molecules between any tworegions where each inter-bonding molecule has a moiety derived from twodiverse molecules of any two respective diverse inter-bonded regionsafter treatment by irradiation (such as an electron beam).

Composite 400 has a layer 402 of a structural material. Layer 402 ismade of metal, polymer, or ceramic. Composite 400 also has a layer 404of a structural material. Layer 404 is also independently made of metal,polymer, or ceramic. It should be noted that the term “structuralmaterial” denotes the contribution of the layer to the overallperformance of the composite as viewed from the intended application ofthe composite where the nature of the outside layers of a compositedetermine its utility in the application (under the presumption that theadhesion between the layers should be acceptable for the application andthat details of the adhesive system in the composite are not otherwiseof performance interest in the application of the composite). In thisregard, a structural layer provides any desired performance property tothe composite as a structure in its intended application. This desiredperformance property provides to the composite any of, withoutlimitation, rigid or flexible support (a structural support layer),chemical or solvent resistance, thermal resistance, flame resistance,adsorption capability, absorption capability, robustness undercompression, robustness under tension, any combination of these, and/orthe like.

Adhesive layer 406 is positioned between layer 402 and layer 404.Adhesive layer 406 is made of polymer. Adhesive layer 406 is, In oneembodiment, bonded to either of layers 402 or 404 by use of irradiation(preferably by electron beam radiation). In this regard, afterirradiation, adhesive layer 406 is inter-bonded at interface 408 or atinterface 410 to the structural material of either layer 402 or layer404, respectively, with at least one inter-bonding moleculecorresponding to the Formula III:ADwhere A is a polymeric carbon chain moiety derived from the polymer ofthe adhesive layer, D is a metallic element derived from the metal ofthe inter-bonded structural material layer when the inter-bondedstructural material layer is made of metal, D is a ceramic moiety from afree radical ceramic derivative of the ceramic of the inter-bondedstructural material layer when the inter-bonded structural materiallayer is made of ceramic, or D is from a free radical polymericderivative of the polymer of the inter-bonded structural material layerwhen the inter-bonded structural material layer is made of polymer.

Adhesive layer 406 is, in a second embodiment, bonded to each of layers402 or 404 by use of irradiation (preferably by electron beamradiation). In this regard, after irradiation, adhesive layer 406 isinter-bonded to the structural material of layer 402 and also to thestructural material of layer 404. Adhesive layer 406 is bonded to layer402 with at least one inter-bonding molecule at interface 408corresponding to Formula IV:ADwhere A is a polymeric carbon chain moiety derived from the polymer ofadhesive layer 406, D is a metallic element derived from the metal oflayer 402 when layer 402 is made of metal, D is a ceramic moiety from afree radical ceramic derivative of the ceramic of layer 402 when layer402 is made of ceramic, and D is from a free radical polymericderivative of the polymer of layer 402 when layer 402 is made ofpolymer.

Adhesive layer 406 is also bonded to layer 404 with at least oneinter-bonding molecule at interface 410 corresponding to Formula V:AEwhere A is a polymeric carbon chain moiety derived from the polymer ofadhesive layer 406, E is a metallic element derived from the metal oflayer 404 when layer 404 is metal, E is a ceramic moiety from a freeradical ceramic derivative of the ceramic of layer 404 when layer 404 isceramic, and E is a polymeric carbon chain moiety from a free radicalpolymeric derivative of the polymer of layer 404 when layer 404 ispolymer.

The use of radiation (preferably electron beam radiation) ininter-bonding the above alternative composite embodiments enables eachcomposite to be assembled by

(a) providing a first layer of structural material (either metal,polymer, or ceramic);

(b) positioning a solid adhesive layer (polymer) onto the first layer;

(c) positioning a second layer of structural material (either metal,polymer, or ceramic) onto the adhesive layer; and

(d) irradiating the first layer, the second layer, and the adhesivelayer with electron beam radiation sufficient to inter-bond the firstlayer to the adhesive layer and to inter-bond the second layer to theadhesive layer.

There are various benefits in this approach to composite manufacture. Byusing a solid adhesive, a benefit is enabled in composite manufacturethat is, in some respects, appreciated from a consideration ofmanufacturing tradeoffs between making a peanut butter sandwich ascompared to making a grilled cheese sandwich from a slice of essentiallysolid cheese or a non-flowing slice of flexible cheese (with irradiationbeing metaphorically represented by the heat that eventually melts thecheese to provide the bonding between the cheese slice and breadslices). In considering peanut butter and cheese as the alternativeadhesives, the peanut butter usually requires resolution of more complexhandling issues than does the slice of cheese. Peanut butter is highlyviscous and requires time, effort, and alignment to be spread (flowablydeposited) onto at least one of the bread slices. Positioning of thesecond bread slice needs a certain degree of careful alignment. In thisregard, repositioning of the second bread slice (in the event of analignment error when the second bread slice was first incorrectlypositioned and pressed against the peanut butter deposited on the firstbread slice) after having been “glued” to the peanut butter firstrequires separating of the second bread slide from the peanut butter;such separating usually tears the bread slice. So, it is important toposition the second bread slice accurately the first time it ispositioned against the peanut butter (zero entropy positioning isneeded). A cheese sandwich, in contrast, is rather easy to assembleprior to heating. The slice of cheese is essentially solid or flexiblysolid in a non-flowable sense, and it doesn't initially adhere to eitherof the bread slices. The cheese is positioned as a unit onto one sliceof bread (rather than being flowably deposited or spread onto the breadslice), and the second slice of bread is conveniently positioned ontothe cheese slice. Prior to heating, the cheese can be repositionedwithout much effort (positioning entropy can be essentially very high upto the time when the cheese is heated) and without destructive impact oneither of the bread slices. In a similar way, construction of acomposite is expedited if the adhesive of the composite is positioned asa solid between the structural layers of the composite. Such an approachworks well in the preferred embodiments if the solid adhesive is theninter-bonded with irradiation (preferably electron beam radiation) toits two structural layers.

The use of irradiation to inter-bond the adhesive to one or both of thelayers also has a benefit in that the polymer of the adhesive layer isreadily capable of having a desired performance property (such as, forexample and without limitation, tensile strength, elongation, modulus,and/or chemical resistance) in the composite that is superior to thesame performance property in either of the layers attached to theadhesive layer. In conjunction with, for example, inter-bonding betweenadhesive 406 and layer 402 and with inter-bonding between adhesive 406and layer 404, the failure point of composite 400 respective to anyparticular so desired performance property will not be in the adhesiveor even in the inter-bonded interfaces of composite 400. This is not thecase in many composites assembled with adhesives that bond either withfunctional group linkages, Van der Waals forces, and/or hydrogen bonds.In this regard, the adhesive layer or the interface between the adhesivelayer and a structural layer is frequently the weak link in theintegrity of traditional composite structures.

The use of irradiation to inter-bond the adhesive to one or both of thelayers also has a benefit in the broad spectrum of materials that arecandidates for the adhesive layer of the composite. In alternativeembodiments, adhesive layer 406 is any of fluoroelastomer,thermoplastic, thermoplastic elastomer, thermoplastic vulcanizate,thermoset plastic, polytetrafluoroethylene, and combinations thereof.

In yet further alternative embodiments, adhesive layer 406 is any ofacrylic acid ester rubber/polyacrylate rubber thermoplastic vulcanizateacrylonitrile-butadiene-styrene, amorphous nylon, cellulosic plastic,ethylene chlorotrifluoro-ethylene, epoxy resin, ethylenetetrafluoroethylene, ethylene acrylic rubber, ethylene acrylic rubberthermoplastic vulcanizate, ethylene-propylene-diamine monomerrubber/polypropylene thermoplastic vulcanizate,tetrafluoroethylene/hexafluoropropylene, fluoroelastomer,fluoroelastomer thermoplastic vulcanizate, fluoroplastic, hydrogenatednitrile rubber, melamine-formaldehyde resin,tetrafluoroethylene/perfluoromethylvinyl ether, natural rubber, nitrilebutyl rubber, nylon, nylon 6, nylon 610, nylon 612, nylon 63, nylon 64,nylon 66, perfluoroalkoxy (tetrafluoroethylene/perfluoromethylvinylether), phenolic resin, polyacetal, polyacrylate, polyamide, polyamidethermoplastic, thermoplastic elastomer, polyamide-imide, polybutene,polybutylene, polycarbonate, polyester, polyester thermoplastic,thermoplastic elastomer, polyesteretherketone, polyethylene,polyethylene terephthalate, polyimide, polymethylmethacrylate,polyolefin, polyphenylene sulfide, polypropylene, polystyrene,polysulfone, polytetrafluoroethylene, polyurethane, polyurethaneelastomer, polyvinyl chloride, polyvinylidene fluoride, ethylenepropylene dimethyl/polypropylene thermoplastic vulcanizate, silicone,silicone-thermoplastic vulcanizate, thermoplastic polyurethane,thermoplastic polyurethane elastomer, thermoplastic polyurethanevulcanizate, thermoplastic silicone vulcanizate, thermoplastic urethane,thermoplastic urethane elastomer,tetrafluoroethylene/hexafluoropropylene/vinylidene fluoride,polyamide-imide, and combinations thereof. In yet further alternativeembodiments, the adhesive layer has a curing agent is admixed into thepolymer of the adhesive layer.

In one composite embodiment, the polymer of any of first layer 402 andsecond layer 404 is halogenated plastic and adhesive layer 406corresponds to Formula II.

At least one layer is, in one embodiment, surface-activated prior toattachment to another layer. In this regard, the surface of essentiallyany halogenated polymer plastic appears to be “etchable” with anelectron beam to yield free radical sites on the surface. In asurprising find, these free radical sites then appear to demonstrateremarkable stability for a period of time. In this regard, as previouslynoted, free-radicals usually react very rapidly with other materials;but free radical polymer chains appear to be much more stable in thefree radical state, especially if the polymeric free radical isconstrained from movement and also constrained from contact with othermaterials that would bond to the free radical site of the polymer chain.Respective to the surprising find, it is believed that electron beambombardment of a surface of a halogenated plastic at an energy level offrom about 0.1 MeRAD to about 40 MeRAD (preferably from about 5 MeRAD toabout 20 MeRAD) provides sufficient energy for dislodging a plurality ofhalogen atoms from the halogenated polymer of the surface and forgenerating thereby a set of initial residual free radical sites inpolymeric chains of the surface upon conclusion of the etching withoutextensive fracturing of the polymer chains, and that maintenance of thesurface in an inert environment and at a temperature sufficient tominimize mobility of the polymer chains of the plastic so that they arekept from mutual interaction sustains at least 99 percent of the freeradical sites of the set of initial residual free radical sites for atleast 4 hours. Furthermore, it is believed that maintenance of thesurface in an inert environment and at a temperature sufficient tominimize mobility of the polymer chains of the plastic so that they arekept from mutual interaction sustains at least 90 percent of the freeradical sites of the set of initial residual free radical sites for atleast 8 hours.

Preferably, the temperature at which the etched material will providethe sustained retention of its free radical sites is room temperature ora temperature lower than room temperature. In one embodiment, the inertenvironment is a noble gas. In another embodiment, the inert environmentis high purity nitrogen. In yet another embodiment, the pressure of theinert environment is less than 0.1 atmospheres. In yet anotherembodiment, a vacuum is applied to the etched material surface. In yetanother embodiment, a static free environment is enabled at the etchedmaterial surface.

Turning now to method embodiments for making the material, composition,and/or article embodiments discussed in the foregoing, one methodembodiment for making a compound is to

(a) generate at least one free radical site on an elastomer molecule toyield a free radical polymeric carbon chain elastomeric molecule; and

(b) bond the free radical polymeric carbon chain elastomeric moleculewith any of, in the alternative, a metallic element, a ceramic moiety,and a polymeric carbon chain thermoplastic moiety;

where the elastomeric molecule has a collective atomic weight of fromabout 350 to about 10,000,000, the thermoplastic moiety is from a freeradical polymeric derivative of a thermoplastic molecule having amolecular weight of from about 120 to about 10,000,000 when thethermoplastic moiety is bonded to the free radical polymeric carbonchain elastomeric molecule, and the ceramic moiety is from a freeradical ceramic compound derivative of a ceramic compound when theceramic moiety is bonded to the free radical polymeric carbon chainelastomeric molecule.

In one embodiment, the elastomer molecule is any of a fluoroelastomermolecule, an acrylic acid ester rubber/polyacrylate rubber molecule, anethylene acrylic rubber molecule, a silicone molecule, a nitrile butylrubber molecule, a hydrogenated nitrile rubber molecule, natural rubbermolecule, a ethylene-propylene-diamine monomer rubber/polypropylenethermoplastic vulcanizate molecule, and a polyurethane molecule.

In an alternative embodiment, the thermoplastic molecule is any of apolyamide molecule, a nylon 6 molecule, a nylon 66 molecule, a nylon 64molecule, a nylon 63 molecule, a nylon 610 molecule, a nylon 612molecule, an amorphous nylon molecule, a polyester molecule, apolyethylene terephthalate molecule, a polystyrene molecule, apolymethyl methacrylate molecule, a thermoplastic polyurethane molecule,a polybutylene molecule, a polyesteretherketone molecule, a polyimidemolecule, a fluoroplastic molecule, a polyvinylidene fluoride molecule,a polysulfone molecule, a polycarbonate molecule, a polyphenylenesulfide molecule, a polyethylene molecule, a polypropylene molecule, apolyacetal molecule, a perfluoroalkoxy(tetrafluoroethylene/perfluoromethylvinyl ether) molecule, atetrafluoroethylene/perfluoromethylvinyl ether molecule, an ethylenetetrafluoroethylene molecule, an ethylene chlorotrifluoroethylenemolecule, a tetrafluoroethylene/hexafluoropropylene/vinylidene fluoridemolecule, a tetrafluoroethylene/hexafluoropropylene molecule, apolyester thermoplastic ester molecule, a polyester ether copolymermolecule, a polyamide ether copolymer molecule, and a polyamidethermoplastic ester molecule.

In one embodiment, the elastomer is a compound according to Formula II.

In a preferred embodiment, the generation of the free radical site onthe elastomer is achieved by irradiating the elastomer molecule withelectron beam radiation (preferably of from about 0.1 MeRAD to about 40MeRAD and, more preferably, from about 5 MeRAD to about 20 MeRAD).

In one embodiment, the free radical generation and the bonding occurwithin a cavity of a mold, where the housing of the mold enablestransmission of an electron beam from an outside surface of the housingthrough the housing surface defining (at least in part) the cavity andthereby to the elastomer molecule. The penetration depth of a particularelectron beam depends upon the strength of the electron beam, thedensity of the housing materials, and the particular material used inthe housing. In this regard, the entire mold housing is, in oneembodiment, made of a material (such as glass, steel, plastic, brass, oraluminum) that will transmit the radiation (preferably an electronbeam). In an alternative embodiment, a portion of the mold housing ismade of a material that will transmit the radiation. In yet anotherembodiment, a beam port (glass, steel, plastic, brass, or aluminum) isembedded into the mold housing and the beam port is made of a materialthat will transmit the radiation. In another approach, the free radicalgeneration and the bonding occur after a shaped article has been formedof the material having the elastomer and then cooled within a cavity ofa mold; the mold is opened and the cooled material then irradiated withan electron beam (prior to removal of the shaped article from the mold)in one embodiment of this approach, or the cooled material is removedfrom the mold prior to being irradiated in another embodiment of thisapproach.

Indeed, in one embodiment, monomers, oligomers, or low molecular weightpolymeric precursors of a higher molecular weight polymer are injectedin liquid form into a mold, and further curing and polymerization ofthese materials into the final article is performed by the use ofelectron beam irradiation.

In another method embodiment, a composition is made by

(a) admixing a dispersed phase of a plurality of vulcanized elastomericportions into a continuous phase of thermoplastic polymer where thedispersed phase of vulcanized elastomer has been previously vulcanizedto provide a compression set value from about 50 to about 100 percent ofthe difference between a non-vulcanized compression set value for theelastomer and a fully-vulcanized compression set value for theelastomer; and

(b) cross-linking the continuous phase.

Preferably, the cross-linking operation inter-bonds the continuous phaseand the dispersed phase with at least one inter-bonding moleculecorresponding to an elastomer-thermoplastic polymer according to FormulaI. In this regard, A is an elastomeric moiety from a free radicalpolymeric derivative derived from the elastomer of the dispersed phasewhere the elastomeric moiety has a collective atomic weight of fromabout 350 to about 10,000,000; and D is a polymeric carbon chainthermoplastic moiety from a free radical polymeric derivative of athermoplastic molecule from the continuous phase where the thermoplasticmolecule has a molecular weight of from about 120 to about 10,000,000.

In one embodiment of this method, the vulcanized elastomer is derivedfrom an elastomer of any of fluoroelastomer, acrylic acid esterrubber/polyacrylate rubber, ethylene acrylic rubber, silicone, nitrilebutyl rubber, hydrogenated nitrile rubber, natural rubber,ethylene-propylene-diamine monomer rubber/polypropylene thermoplasticvulcanizate, polyurethane, and combinations thereof.

In one embodiment of this method, the thermoplastic polymer is any ofpolyamide, nylon 6, nylon 66, nylon 64, nylon 63, nylon 610, nylon 612,amorphous nylon, polyester, polyethylene terephthalate, polystyrene,polymethyl methacrylate, thermoplastic polyurethane, polybutylene,polyesteretherketone, polyimide, fluoroplastic, polyvinylidene fluoride,polysulfone, polycarbonate, polyphenylene sulfide, polyethylene,polypropylene, polyacetal polymer, polyacetal, perfluoroalkoxy(tetrafluoroethylene/perfluoromethylvinyl ether),tetrafluoroethylene/perfluoromethylvinyl ether, ethylenetetrafluoroethylene, ethylene chlorotrifluoroethylene,tetrafluoroethylene/hexafluoro-propylene/vinylidene fluoride,tetrafluoroethylene/hexafluoropropylene, polyester thermoplastic ester,polyester ether copolymer, polyamide ether copolymer, polyamidethermoplastic ester, and combinations thereof.

In one embodiment, the cross-linking is achieved by irradiating thedispersed and continuous phases with electron beam radiation (preferablyof from about 0.1 MeRAD to about 40 MeRAD and, more preferably, fromabout 5 MeRAD to about 20 MeRAD).

In one embodiment, the cross-linking is achieved by irradiating thedispersed and continuous phases within a cavity of the previouslydescribed mold, where the housing of the mold enables transmission of anelectron beam from an outside surface of the housing through a surfaceof the cavity and thereby to the dispersed and continuous phases.

In one embodiment, each of the elastomeric portions are admixed toprovide a cross-sectional diameter (in either essentially spherical orfilament formed portions) from about 0.1 microns to about 100 microns.

In one embodiment, the dispersed phase provides from about 20 weightpercent to about 90 weight percent of the admixture.

In another method embodiment, a composition is made by

(a) admixing a dispersed phase of a plurality of elastomeric portionsinto a continuous phase of thermoplastic polymer; and

(b) cross-linking the continuous and dispersed phases.

Preferably, the cross-linking operation inter-bonds the continuous phaseand the dispersed phase with at least one inter-bonding moleculecorresponding to an elastomer-thermoplastic polymer according to FormulaI. In this regard, A is an elastomeric moiety from a free radicalpolymeric derivative derived from an elastomer molecule of the dispersedphase where A has a collective atomic weight of from about 350 to about10,000,000; and D is from a free radical polymeric derivative of athermoplastic molecule from the continuous phase, the thermoplasticmolecule having a molecular weight of from about 120 to about10,000,000.

In one embodiment of this method, the dispersed phase is elastomer ofany of fluoroelastomer, acrylic acid ester rubber/polyacrylate rubber,ethylene acrylic rubber, silicone, nitrile butyl rubber, hydrogenatednitrile rubber, natural rubber, ethylene-propylene-diamine monomerrubber/polypropylene thermoplastic vulcanizate, polyurethane, andcombinations thereof.

In one embodiment of this method, the thermoplastic polymer is any ofpolyamide, nylon 6, nylon 66, nylon 64, nylon 63, nylon 610, nylon 612,amorphous nylon, polyester, polyethylene terephthalate, polystyrene,polymethyl methacrylate, thermoplastic polyurethane, polybutylene,polyesteretherketone, polyimide, fluoroplastic, polyvinylidene fluoride,polysulfone, polycarbonate, polyphenylene sulfide, polyethylene,polypropylene, polyacetal polymer, polyacetal, perfluoroalkoxy(tetrafluoroethylene/perfluoromethylvinyl ether),tetrafluoroethylene/perfluoromethylvinyl ether, ethylenetetrafluoroethylene, ethylene chlorotrifluoroethylene,tetrafluoroethylene/hexafluoro-propylene/vinylidene fluoride,tetrafluoroethylene/hexafluoropropylene, polyester thermoplastic ester,polyester ether copolymer, polyamide ether copolymer, polyamidethermoplastic ester, and combinations thereof.

In one embodiment, the cross-linking is achieved by irradiating thedispersed and continuous phases with electron beam radiation (preferablyof from about 0.1 MeRAD to about 40 MeRAD and, more preferably, fromabout 5 MeRAD to about 20 MeRAD).

In one embodiment, the cross-linking is achieved by irradiating thedispersed and continuous phases within a cavity of the previouslydescribed mold, where the housing of the mold enables transmission of anelectron beam from an outside surface of the housing through a surfaceof the cavity and thereby to the dispersed and continuous phases.

In one embodiment, each of the elastomeric portions are admixed toprovide a cross-sectional diameter (in either essentially spherical orfilament formed portions) from about 0.1 microns to about 100 microns.

In one embodiment, the dispersed phase provides from about 20 weightpercent to about 90 weight percent of the admixture.

In yet another method embodiment, a composition is made by

(a) admixing a dispersed phase of a plurality of thermoplastic portionsinto a continuous phase of elastomer; and

(b) cross-linking the continuous and dispersed phases.

Preferably, the cross-linking operation inter-bonds the continuous phaseand the dispersed phase with (at least one) inter-bonding molecule(s)corresponding to an elastomer-thermoplastic polymer according to FormulaI. In this regard, A is an elastomeric moiety from a free radicalpolymeric derivative derived from an elastomer molecule of the dispersedphase where A has a collective atomic weight of from about 350 to about10,000,000; and D is from a free radical polymeric derivative of athermoplastic molecule from the continuous phase, the thermoplasticmolecule having a molecular weight of from about 120 to about10,000,000.

In one embodiment of this method, the continuous phase is elastomer ofany of fluoroelastomer, acrylic acid ester rubber/polyacrylate rubber,ethylene acrylic rubber, silicone, nitrile butyl rubber, hydrogenatednitrile rubber, natural rubber, ethylene-propylene-diamine monomerrubber/polypropylene thermoplastic vulcanizate, polyurethane, andcombinations thereof.

In one embodiment of this method, the thermoplastic polymer is any ofpolyamide, nylon 6, nylon 66, nylon 64, nylon 63, nylon 610, nylon 612,amorphous nylon, polyester, polyethylene terephthalate, polystyrene,polymethyl methacrylate, thermoplastic polyurethane, polybutylene,polyesteretherketone, polyimide, fluoroplastic, polyvinylidene fluoride,polysulfone, polycarbonate, polyphenylene sulfide, polyethylene,polypropylene, polyacetal polymer, polyacetal, perfluoroalkoxy(tetrafluoroethylene/perfluoromethylvinyl ether),tetrafluoroethylene/perfluoromethylvinyl ether, ethylenetetrafluoroethylene, ethylene chlorotrifluoroethylene,tetrafluoroethylene/hexafluoro-propylene/vinylidene fluoride,tetrafluoroethylene/hexafluoropropylene, polyester thermoplastic ester,polyester ether copolymer, polyamide ether copolymer, polyamidethermoplastic ester, and combinations thereof.

In one embodiment, the cross-linking is achieved by irradiating thedispersed and continuous phases with electron beam radiation (preferablyof from about 0.1 MeRAD to about 40 MeRAD and, more preferably, fromabout 5 MeRAD to about 20 MeRAD).

In one embodiment, the cross-linking is achieved by irradiating thedispersed and continuous phases within a cavity of the previouslydescribed mold, where the housing of the mold enables transmission of anelectron beam from an outside surface of the housing through a surfaceof the cavity and thereby to the dispersed and continuous phases.

In one embodiment, each of the thermoplastic portions are admixed toprovide a cross-sectional diameter (in either essentially spherical orfilament formed portions) from about 0.1 microns to about 100 microns.

In yet another method embodiment, a composition is made by

(a) admixing molecules of an elastomer and molecules of a thermoplasticinto a polymeric admixture; and

(b) irradiating the polymeric admixture with electron beam radiation;wherein each of the elastomer molecules have a molecular weight of fromabout 350 to about 10,000,000, and each of the thermoplastic moleculeshas a molecular weight of from about 120 to about 10,000,000.

In this embodiment, the elastomer and the thermoplastic preferablyinitially exist as separate masses of an elastomer fluid material and athermoplastic fluid material, with each of the two materials havingessentially similar viscosities. The two fluid materials are thenadmixed and agitated to mutually disperse the individual molecules intoa blended single phase admixture. The admixture is then irradiated tocrosslink the materials and also derive at least one instance of acompound corresponding to an elastomer-thermoplastic polymer accordingto Formula I. In this regard, A is an elastomeric moiety from a freeradical polymeric derivative derived from an elastomer molecule of thedispersed phase where A has a collective atomic weight of from about 350to about 10,000,000; and D is from a free radical polymeric derivativeof a thermoplastic molecule from the continuous phase, the thermoplasticmolecule having a molecular weight of from about 120 to about10,000,000.

In one embodiment of this method, the elastomer is any offluoroelastomer, acrylic acid ester rubber/polyacrylate rubber, ethyleneacrylic rubber, silicone, nitrile butyl rubber, hydrogenated nitrilerubber, natural rubber, ethylene-propylene-diamine monomerrubber/polypropylene thermoplastic vulcanizate, polyurethane, andcombinations thereof.

In one embodiment of this method, the thermoplastic polymer is any ofpolyamide, nylon 6, nylon 66, nylon 64, nylon 63, nylon 610, nylon 612,amorphous nylon, polyester, polyethylene terephthalate, polystyrene,polymethyl methacrylate, thermoplastic polyurethane, polybutylene,polyesteretherketone, polyimide, fluoroplastic, polyvinylidene fluoride,polysulfone, polycarbonate, polyphenylene sulfide, polyethylene,polypropylene, polyacetal polymer, polyacetal, perfluoroalkoxy(tetrafluoroethylene/perfluoromethylvinyl ether),tetrafluoroethylene/perfluoromethylvinyl ether, ethylenetetrafluoroethylene, ethylene chlorotrifluoroethylene,tetrafluoroethylene/hexafluoro-propylene/vinylidene fluoride,tetrafluoroethylene/hexafluoropropylene, polyester thermoplastic ester,polyester ether copolymer, polyamide ether copolymer, polyamidethermoplastic ester, and combinations thereof.

In one embodiment, the cross-linking is achieved by irradiating theadmixture with electron beam radiation (preferably of from about 0.1MeRAD to about 40 MeRAD and, more preferably, from about 5 MeRAD toabout 20 MeRAD).

In one embodiment, the cross-linking is achieved by irradiating theadmixture within a cavity of the previously described mold, where thehousing of the mold enables transmission of an electron beam from anoutside surface of the housing through a surface of the cavity andthereby to the dispersed and continuous phases.

In one embodiment, the elastomer provides from about 20 weight percentto about 90 weight percent of the admixture.

A further method embodiment related to polymer chain synthesis usingirradiation (preferably electron beam) in interim free radicalgeneration provides a path for making new types of polymers and newtypes of elastomers (including fluoroelastomers). In this regard, andwith reference again to FIG. 1, Region 110 defines blends of respectivetetrafluoroethyl, hexfluoropropyl, and vinylidyl fluoride overall blockamounts that traditionally have not generated useful co-polymers.However, it is believed that, through a process of building differentmatrix orientations than have traditionally occurred in fluoroelastomermanufacture, new and useful fluoroelastomer compounds are now availablefrom blends of respective tetrafluoroethyl, hexfluoropropyl, andvinylidyl fluoride overall block amounts that would fall with Region 110(as well as in Regions 101, 104, 106, and 108) of ternary compositiondiagram 100 of FIG. 1.

In overview of this general approach to making new polymers, irradiation(preferably E-beam irradiation) of a type that can generate free radicalsites on polymer chains at interim points between the ends of theindividual chains is applicable in many diverse polymeric blends and inpolymer chain synthesis where the polymer chain is built with periodicfree radical generation on the oligomer and precursor interim polymericchains (between the endpoints) during polymeric synthesis. Exampleembodiments of materials and admixtures for such treatment includenon-FKM elastomers/fluoro-plastics oligomer mixtures, FKMelastomers/non-fluoroplastic thermoplastics (TP) or thermoplasticelastomers (TPE) oligomer mixtures, polyurethane (PU)elastomers/thermoplastic (TP) or thermoplastic elastomers (TPE) oligomermixtures, ACM or AEM elastomers/thermoplastic (TP) or thermoplasticelastomers (TPE) oligomer mixtures, silicone elastomers/thermoplastic(TP) or thermoplastic elastomers (TPE) oligomer mixtures, NBR or HNBRelastomers/thermoplastic (TP) or thermoplastic elastomers (TPE) oligomermixtures, EPDM elastomers/thermoplastic (TP) oligomer mixture, and thelike. Exemplary embodiments of low molecular weight thermoplastics inthis regard also include cyclic butylene terephthalate (CBT) and polycyclohexylene dimethylene terephthalate (PCT) oligomers.

In additional embodiments, the same concepts pertain to yet other lowmolecular weight elastomers and other low molecular weightthermoplastics. Example embodiments of materials and admixtures for suchtreatment include ACM, AEM, PU, silicone (MVQ), HNBR, EPDM, NBR, naturalrubber, and the like. Example embodiments of thermoplastic oligomersmaterials and admixtures for such treatment include cyclic butyleneterephthalate (CBT) oligomers, poly cyclohexylene dimethyleneterephthalate (PCT) oligomers, and the like. Exemplary fluoro-plasticsinclude polyvinylidene fluoride, ethylene tetrafluoroethylene, ethylenechlorotrifluoro-ethylene, tetrafluoro-ethylene/hexafluoropropylene,tetrafluoroethylene/hexafluoropropylene/vinylidene fluoride,tetrafluoroethylene/perfluoromethylvinyl ether, perfluoroalkoxy(tetrafluoroethylene/perfluoromethylvinyl ether), and the like.Exemplary TPEs include AtoFina's Pebax, DuPont's Hytrel, Shell's Kraton,BASF's Esthane, AES's Santoprene, DSM's Sarlink, etc. Exemplarynon-fluoroplastic thermoplastics (TP) include polyamides (nylons),polyesters, polyolefins, PPS, PEEK, Torlon, polysulfone, TPUs, ABS, PVC,PS, PMMA, PC, PB, cellulosic plastics, polyacrylics, polyacetals, andthe like. Exemplary thermoset materials include phenolic resin,melamine-formaldehyde resin, epoxy resin, and the like.

There are several embodiments enabled in this approach of polymer chainsynthesis using irradiation (preferably electron beam) in interim freeradical generation. One embodiment admixture has

(a) a first elastomer selected from the group of fluoroelastomer,acrylic acid ester rubber/polyacrylate rubber, ethylene acrylic rubber,silicone, nitrile butyl rubber, hydrogenated nitrile rubber, naturalrubber, ethylene-propylene-diamine monomer rubber/polypropylenethermoplastic vulcanizate, and polyurethane;

(b) a second elastomer from same group, but where the second elastomeris a different elastomer from the first elastomer; and

(c) polymer compounds having at least one first moiety (having acollective atomic weight of from about 350 to about 10,000,000) derivedfrom a free radical polymeric derivative derived from the firstelastomer, and at least one second moiety (also having a collectiveatomic weight of from about 350 to about 10,000,000) from a free radicalpolymeric derivative derived from the second elastomer. The firstelastomer and all instances of the first moiety in the bi-elastomericpolymer compound(s) of this embodiment combine to provide from about 5weight percent to about 95 weight percent of the admixture composition.This embodiment is made by admixing the first elastomer and secondelastomer into an primary admixture, and irradiating the primaryadmixture.

Another embodiment admixture has

(a) a first thermoplastic selected from the group of polyamide, nylon 6,nylon 66, nylon 64, nylon 63, nylon 610, nylon 612, amorphous nylon,polyester, polyethylene terephthalate, polystyrene, polymethylmethacrylate, thermoplastic polyurethane, polybutylene,polyesteretherketone, polyimide, fluoroplastic, polyvinylidene fluoride,polysulfone, polycarbonate, polyphenylene sulfide, polyethylene,polypropylene, polyacetal, perfluoroalkoxy(tetrafluoroethylene/perfluoromethylvinyl ether),tetrafluoroethylene/perfluoromethylvinyl ether, ethylenetetrafluoroethylene, ethylene chlorotrifluoroethylene,tetrafluoroethylene/hexafluoropropylene/vinylidene fluoride,tetrafluoroethylene/hexafluoropropylene, polyester thermoplastic ester,polyester ether copolymer, polyamide ether copolymer, and polyamidethermoplastic ester;

(b) a second thermoplastic from same group, but where the secondthermoplastic is a different thermoplastic from the first thermoplastic;and

(c) polymer compounds having at least one first moiety (having acollective atomic weight of from about 120 to about 10,000,000) from afree radical polymeric derivative derived from the first thermoplastic,and at least one second moiety (having a collective atomic weight offrom about 120 to about 10,000,000) from a free radical polymericderivative derived from the second thermoplastic. The firstthermoplastic and all instances of the first moiety in thebi-thermoplastic polymer compound(s) of this embodiment combine toprovide from about 5 weight percent to about 95 weight percent of theadmixture composition. This embodiment is made by admixing the firstthermoplastic and second thermoplastic into an primary admixture, andirradiating the primary admixture.

Turning to particular fluoropolymer and/or fluoroelastomer embodiments,with respect to the alternative structures enabled by irradiation at thecritical oligomer stage, it is also believed that, through a process ofbuilding different matrix orientations than have traditionally occurredin fluoroelastomer manufacture in the blends of tetrafluoroethyl,hexfluoropropyl, and vinylidyl fluoride overall block amountstraditionally used in fluoroelastomers, that new and usefulfluoroelastomer compounds in a new structural context are now availablefrom blends of respective tetrafluoroethyl, hexfluoropropyl, andvinylidyl fluoride overall block amounts that would fall within Region101 of ternary composition diagram 100 of FIG. 1. Indeed newfluoroelastomer or fluoropolymer materials should result fromtetrafluoroethyl, hexfluoropropyl, and vinylidyl fluoride overall blockamounts that would fall with any of Regions 101, 102, 104, 106, 108, and110 of ternary composition diagram 100 of FIG. 1. The electron beamirradiation triggers the curing (cross-linking) reaction in the FKMoligomer phase or stage by generating free radical sites, as previouslyoccupied by fluorine molecules on the FKM oligomer molecular chains. Ingenerating free radical sites on subsequent precursor polymer chains(larger than the oligomer stage but still premature respective to theultimate desired chain length), the electron beam derives a free radicalsites as previously occupied by fluorine molecules on the FKM precursormolecular chain.

The benefits of irradiation (preferably E-beam irradiation) includeimproved flow characteristics (due to a lower viscosity and lowermelting point in branched chain polymers respective to the viscosity instraight chained polymers of comparable molecular weight) andprocessability (due to a lower processing temperature and pressurerespective to the processing temperature and pressure for straightchained polymers of comparable molecular weight). Additionally, surfaceand internal textures are comparably improved with an elimination of theneed for chemical curing agents and/or chemical curing packages (insofaras such agents/packages generate undesirable gases as they react duringprocessing). The curing process can be executed in situ in a mold byusing an E-beam compatible (penetrable) mold of glass or thin metal orceramic. Physical properties and chemical resistance of E-beam cured FKMelastomers are adjustable respective to molecular weight and the degreeof cross-linking density achieved with each irradiative treatment duringthe E-beam augmented curing process. The irradiative curing approacheliminates, in one embodiment, post cure curing processes and alsoenables FKM elastomers to be molded and cured without the addition ofexpensive cure-site monomers (CSM) or chemical curing packages needed intraditional curing techniques.

Other properties, such as tensile properties, wear properties,compression set, service temperature, heat deflection temperature,dynamic fatigue resistance, fluid (chemical) resistance, creepresistance, and the like are beneficially adjusted in various branchedchain polymeric embodiments respective to the comparable properties inthe traditional essentially linear polymer structures. In oneapplication embodiment, for example, E-beam cured seals of an FKMoligomer/fluoroplastic oligomer mixture provide superior sealperformance characteristics to seals made of chemically curedconventional FKM-TPV with high molecular weight FKM elastomer andfluoroplastic blends.

In one embodiment of a method for using irradiatively augmentedpolymerization,

(a) tetrafluoroethylene (TFE), hexfluoropropylene (HFP), and vinylidenefluoride (VdF) are admixed in proportions according to values withinRegion 110 of FIG. 1 so that a reaction admixture is formed;

(b) the reaction admixture is then reacted to generate a set offluoropolymeric oligomers (an oligomer is a polymer compound which isbuilt from about 2 to about 5 monomer units) within the reactionadmixture and form thereby a fluoropolymeric oligomeric precursoradmixture;

(c) the fluoropolymeric oligomeric precursor admixture is thenirradiated to form free radical sites on individual fluoropolymericoligomers of the set and generate thereby a set of free radical oligomerderivatives in the fluoropolymeric oligomeric precursor admixture; and

(d) the fluoropolymeric oligomeric precursor admixture is furtherreacted to derive the fluoroelastomer compound from the free radicaloligomer derivatives.

In an alternative embodiment of such a method

(a) tetrafluoroethylene (TFE), hexfluoropropylene (HFP), and vinylidenefluoride (VdF) are admixed in proportions according to values withinRegion 101 of FIG. 1 so that a reaction admixture is formed;

(b) the reaction admixture is then reacted to generate a set offluoropolymeric oligomers (an oligomer is a polymer compound which isbuilt from about 2 to about 5 monomer units) within the reactionadmixture and form thereby a fluoropolymeric oligomeric precursoradmixture;

(c) the fluoropolymeric oligomeric precursor admixture is thenirradiated to form free radical sites on individual fluoropolymericoligomers of the set and generate thereby a set of free radical oligomerderivatives in the fluoropolymeric oligomeric precursor admixture; and

(d) the fluoropolymeric oligomeric precursor admixture is furtherreacted to derive the fluoroelastomer compound from the free radicaloligomer derivatives.

In one embodiment of either of the above methods, the subsequent interimpolymers (larger than the oligomer stage but less than theeventually-desired molecular weight) are irradiated to further generatefree radical sites at least one additional interim molecular weight inthe continued molecular weight increase of the polymerizingfluoropolymers.

Turning now to a method embodiment for making a composite, a compositeis made by

(a) providing a first layer of structural material (metal, polymer, orceramic);

(b) positioning a solid adhesive layer of polymer onto the first layer;

(c) positioning a second layer of structural material (metal, polymer,or ceramic); and

(d) irradiating the first layer, the second layer, and the adhesivelayer with electron beam radiation sufficient to inter-bond the firstlayer to the adhesive layer and to inter-bond the second layer to theadhesive layer.

In one embodiment, the irradiating is achieved by irradiating thedispersed and continuous phases with electron beam radiation (preferablyof from about 0.1 MeRAD to about 40 MeRAD and, more preferably, fromabout 5 MeRAD to about 20 MeRAD).

In one embodiment, the adhesive layer is bonded to the structuralmaterial of the first layer with at least one first inter-bondingmolecule corresponding to Formula IV, and the adhesive layer is alsobonded to the structural material of the second layer with at least onesecond inter-bonding molecule corresponding to the Formula V. In thisembodiment, the adhesive layer has a characteristic performance property(such as, for example without limitation tensile strength, elongation,modulus, and chemical resistance) superior to the performance propertyof either of the first or second layer. In this regard, the compositewill fail, respective to the particular concern addressed by theperformance property, on the basis of the performance of the layersrather than the performance of the adhesive. So, for instance,separation of the composite under a force beyond the design capabilityof the composite should occur within either the first or second layersrather than in the adhesive layer. Such a benefit in compositeconstruction is frequently not achievable with adhesives that spread orflow into position and then are cured or otherwise solidified to bond tothe outer layers of the composite.

In one embodiment, the polymer of the adhesive layer is any offluoroelastomer, acrylic acid ester rubber/polyacrylate rubber, ethyleneacrylic rubber, silicone, nitrile butyl rubber, hydrogenated nitrilerubber, natural rubber, ethylene-propylene-diamine monomerrubber/polypropylene thermoplastic vulcanizate, polyurethane, andcombinations thereof.

In an alternative embodiment, the polymer of the adhesive layer isselected from the group consisting of acrylic acid esterrubber/polyacrylate rubber thermoplastic vulcanizateacrylonitrile-butadiene-styrene, amorphous nylon, cellulosic plastic,ethylene chlorotrifluoro-ethylene, epoxy resin, ethylenetetrafluoroethylene, ethylene acrylic rubber, ethylene acrylic rubberthermoplastic vulcanizate, ethylene-propylene-diamine monomerrubber/polypropylene thermoplastic vulcanizate,tetrafluoroethylene/hexafluoropropylene, fluoroelastomer,fluoroelastomer thermoplastic vulcanizate, fluoroplastic, hydrogenatednitrile rubber, melamine-formaldehyde resin,tetrafluoroethylene/perfluoromethylvinyl ether, natural rubber, nitrilebutyl rubber, nylon, nylon 6, nylon 610, nylon 612, nylon 63, nylon 64,nylon 66, perfluoroalkoxy (tetrafluoroethylene/perfluoromethylvinylether), phenolic resin, polyacetal, polyacrylate, polyamide, polyamidethermoplastic elastomer, polyamide-imide, polybutene, polybutylene,polycarbonate, polyester, polyester thermoplastic elastomer,polyesteretherketone, polyethylene, polyethylene terephthalate,polyimide, polymethylmethacrylate, polyolefin, polyphenylene sulfide,polypropylene, polystyrene, polysulfone, polytetrafluoroethylene,polyurethane, polyurethane elastomer, polyvinyl chloride, polyvinylidenefluoride, ethylene propylene dimethyl/polypropylene thermoplasticvulcanizate, silicone, silicone-thermoplastic vulcanizate, thermoplasticpolyurethane, thermoplastic polyurethane elastomer, thermoplasticpolyurethane vulcanizate, thermoplastic silicone vulcanizate,thermoplastic urethane, thermoplastic urethane elastomer,tetrafluoroethylene/hexafluoropropylene/vinylidene fluoride,polyamide-imide, and combinations thereof.

In one embodiment, a curing agent is admixed into the polymer of theadhesive layer.

In one embodiment, the polymer of the polymer of any of the first layerand the second layer is halogenated plastic and the adhesive layercorresponds to Formula II.

In one embodiment, within a cavity of the previously described mold,where the housing of the mold enables transmission of an electron beamfrom an outside surface of the housing through a surface of the cavityand thereby to the composite.

In one embodiment, positioning of the second layer further involvescompressing the first layer and the second layer against the adhesivelayer.

An embodiment of a method for surface preparation of any item (such as ahalogenated polymer surface of a composite precursor assembly) isprovided by etching an article made of halogenated polymer through theprocess of

(a) etching a surface of the article with an electron beam; and

(b) placing the surface in an inert environment at a predeterminedtemperature;

where the electron beam energizes the surface with sufficient energy fordislodging a plurality of halogen atoms from the halogenated polymer ofthe surface and for generating thereby a set of initial residual freeradical sites in polymeric chains of the surface upon conclusion of theetching, and the inert environment and the predetermined temperature areestablished to sustain at least 99 percent of the free radical sites ofthe set of initial residual free radical sites for at least 4 hours.

In one embodiment, the inert environment and the predeterminedtemperature are sufficient for sustaining at least 90 percent of thefree radical sites of the set of initial residual free radical sites forat least 8 hours.

In one embodiment, the inert environment is a noble gas. In anotherembodiment, the inert environment is high purity nitrogen. In yetanother embodiment, the pressure of the inert environment is less than0.1 atmospheres. In yet another embodiment, a vacuum is applied to theetched material surface. In yet another embodiment, a static freeenvironment is enabled at the etched material surface.

In one embodiment, the cross-linking is achieved by irradiating theassembled layers with electron beam radiation (preferably of from about0.1 MeRAD to about 40 MeRAD and, more preferably, from about 5 MeRAD toabout 20 MeRAD).

The presence of inter-bonding molecules in the described embodiments isdetected and confirmed subsequent to irradiation (preferably electronbeam irradiation) treatment by use of techniques such as X-rayDiffraction, Fourier transform infrared analysis, gel permeationchromatography, and nuclear magnetic resonance such as either ofFluorine 19 Nuclear Magnetic Resonance (F₁₉ NMR) and Carbon 13 NuclearMagnetic Resonance (C₁₃ NMR).

In some embodiments, the polymeric compositions are analyzed or purifiedby a process of contacting the material with a ketone type polar solvent(such as methyl-ethyl ketone or acetone) to disperse the polymericmolecules into solution. A “weak” solvent is used for dissolution ofoligomer samples during polymerization, and a “strong” solvent fordissolution of mature polymer chains of greater molecular weight.Chromatography or another diffusive separation technique is then used topurify and/or analyze for particular molecular components in thesolution.

Some composite embodiments also benefit from havingpolytetrafluoroethylene as a structural material as further preparedwith synthesized polymer chains (especially from materials having ahalogenated polymer phase or portion) from a process initiated with freeradical formation derived from irradiation (especially electron beamradiation). However, these composite embodiments do not benefit from theuse of a solid (essentially non-flowable) adhesive; so challenges akinto making a peanut butter sandwich must be endured. These embodimentsdo, however, facilitate incorporation of polytetrafluoroethylene intothe composite for certain applications, and the superior performanceproperties of polytetrafluoroethylene are well worth the effort neededto handle the flowable adhesive involved.

In one embodiment of such a composite where adhesive is deposited as aliquid material, the adhesive is a bonding material for adhering an itemmade of PTFE to another structural item (to a second item made ofnon-PTFE (polymer, wood, ceramic, leather, or metal) with a very goodbond. This bonding material provides a “handle” to “link” to freeradical bonds in the PTFE surface to be bonded. The number of the freeradical bonds in the PTFE surface is dramatically increased when thesurface is etched (preferably by irradiation with an electron beam) toremove a substantial portion of the fluorine radicals from the PTFEchains in the surface. The other mission of the bonding material is toprovide a “handle” for linking the PTFE chains to the (second)structural material; this is usually less difficult than linking to PTFEbecause most structural materials have enough surface tension to “stick”to at least some generally adhesive polymers. Finally, the bondingmaterial needs to be internally coherent so that the “handles” to thePTFE part of the composite and the “handles” to the structural materialpart of the composite are themselves held directly or indirectly inclose proximity. Since the bonding material is generally spread as acoating onto the components to be joined into the composite, it isconvenient for the bonding material to be in the initial form of aliquid having a viscosity that facilitates the spreading or coatingoperation.

In one embodiment, the structural support material portion of acomposite (the structural support material portion made of non-PTFEpolymer, wood, ceramic, or metal) is bonded to an etched surface of thePTFE portion of the composite (the PTFE article) at an interfaceessentially filled with cured admixture of from about 10 to about 90weight percent (preferably from about 20 to about 60 weight percent;more preferably about 50 weight percent)tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer,from about 0.01 to about 1 weight percent polyethylene-oxide-modifiedsilicone polymer coupling agent, not more than 1 weight percent water,and a remainder of oxygen-radical-containing copolymer. In this regard,the oxygen-radical-containing copolymer has at least one “oxy” or —O—radical (oxygen atom radical having 2 bonds attached to two respectiveother atoms) in the characteristic polymer molecule. In this regard, theoxygen-radical-containing copolymer molecule is, In one embodiment, acured epoxy polymer or cured phenoxy where the “oxy” radical provides alink between two other carbon atoms in the polymer chain. In anotherembodiment, the oxygen-radical-containing copolymer is a hydroxylateddiamine-diepoxide derivative copolymer molecule, where the “oxy” radicalis in hydroxyl radicals of the polymer chain. In such a copolymermolecule, each of the two nitrogen radicals of a diamine is, forexample, connected to two separate hydroxylated carbon chain moieties inthe general matrix of the crosslinked polymer macromolecule.

The cured admixture (of from about 10 to about 90 weight percenttetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer,from about 0.01 to about 1 weight percent polyethylene-oxide-modifiedsilicone polymer coupling agent, not more than 1 weight percent water,and a remainder of oxygen-radical-containing copolymer) results fromdewatering and curing of an aqueous admixture that was coated onto theetched surface and then cured. This aqueous admixture is admixed fromabout 10 to about 90 weight percent (preferably from about 20 to about60 weight percent; more preferably about 50 weight percent)fluoropolymer aqueous emulsion and a remainder ofoxygen-radical-containing copolymer aqueous solution.

The fluoropolymer aqueous emulsion has from about 20 to about 60 weightpercent (preferably from about 46.5 to about 51.5 weight percent)tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride emulsifiedterpolymer, a pH from about 6 to about 10 (preferably from about 8 toabout 9), a specific gravity from about 1.1 to about 1.5 grams permilliliter, and a viscosity from about 4 to about 12 Mega Pascal Seconds(preferably from about 9 to about 10 Mega Pascal Seconds). One source ofthis is tetrafluoro-ethylene/hexafluoropropylene/vinylidene fluorideFluorothermoplastic from Dyneon LLC (Oakdale, Minn.) under the productidentifier tetrafluoroethylene/hexafluoropropylene/vinylidenefluoride-350C. tetrafluoro-ethylene/hexafluoropropylene/vinylidenefluoride-350C provides fluoropolymer aqueous emulsion havingtetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymerfrom about 46.5 to about 51.5 weight percent, a pH from about 8 to about9, and a viscosity from about 9 to about 10 Mega Pascal Seconds.

Turning now to the oxygen-radical-containing copolymer aqueous solutionwith is admixed with the fluoropolymer aqueous emulsion to form theaqueous admixture, the oxygen-radical-containing copolymer aqueoussolution has

(1) from about 20 to about 60 weight percent oxygen-radical-containingcopolymer having a softening temperature of from about 25 to about 180degrees Celsius (preferably from about 65 to about 155 degrees Celsius),a specific gravity from about 1.1 to about 1.5 grams per milliliter, andan estimated equivalent molecular weight from about 100 to about 10,000(preferably from about 450 to about 3000), The oxygen-radical-containingcopolymer is, in various embodiments, any of an epoxy polymer, a phenoxypolymer, or a hydroxylated diamine-diepoxide derivative copolymer, and

(2) from about 0.01 to about 1 weight percent (preferably from about0.05 to about 0.5 weight percent) polyethylene-oxide-modified siliconepolymer coupling agent having a wax melting temperature of from about 25to about 50 degrees Celsius (preferably from about 25 to about 45degrees Celsius).

One embodiment of an epoxy-polymer-based oxygen-radical-containingcopolymer aqueous solution is Chemlock™ aqueous epoxy silane solutionfrom Lord Corporation. Another embodiment is made by blending an epoxyresin (such as any of GT 7071, GT 7072, GT 7014, GT 6097, or GT 6609epoxy resins from Ciba Corporation) with CoatOSil™ 2400polyethylene-oxide modified silicone copolymer coupling agent fromCrompton Corporation. Estimated equivalent molecular weights for GT7071, GT 7072, GT 7014, GT 6097, and GT 6609 epoxy resins varyprogressively from about 450 (GT 7071) to about 2,800 (GT 6609).

In other embodiments, the oxygen-radical-containing copolymer isalternatively a hydroxylated diamine-diepoxide derivative copolymer or aphenoxy. In the case of a phenoxy, the estimated equivalent molecularweight is as high as 10,000. In each embodiment of a composite, theparticular physical properties of the oxygen-radical-containingcopolymer and polyethylene-oxide-modified silicone polymer couplingagent are pinpointed to provide efficacy with the particular materialused for the support component.

In alternative embodiments, the structural support material portionrespectively is made of a polymer of any of polyester thermoplasticelastomer (such as Dupont's Hytrel™ polyester elastomer), polyamidethermoplastic elastomer (such as Atofina's Pebax™ polyamidethermoplastic elastomer), thermoplastic urethane elastomer,fluoroelastomer, ethylene acrylic rubber thermoplastic vulcanizate (suchas a Dupont experimental AEM-TPV also commonly known as ETPV), acrylicacid ester rubber/polyacrylate rubber thermoplastic vulcanizate (such asZeon Chemical's Zeotherm™ acrylic acid ester rubber/polyacrylate rubberthermoplastic vulcanizate), silicone-thermoplastic vulcanizate (such asa Dow Corning experimental VMQ-TPV also commonly known as TPSiV),polyether-block co-polyamide polymer (such as Modified PolymerComponents' Pebax™ polyether-block co-polyamide resin),ethylene-propylene-diamine monomer rubber/polypropylene thermoplasticvulcanizate (such as Advanced Elastomeric System's Santoprene™vulcanizate), polyamide, polyester, polyolefin, polyphenylene-sulfide,polyether-ether ketone, polyamide-imide, polysulfone, thermoplasticurethane, acrylonitrile-butadiene-styrene, polyvinyl chloride,polymethylmethacrylate, polycarbonate, polybutene, cellulosic plastic,polyacrylate, or polyacetal. Polymers made of combinations of these areused in other embodiments.

In yet further embodiments, the structural support material portion ismade of any of steel, carbon steel, stainless steel, brass, bronze, oraluminum.

Turning now to the process by which a polytetrafluoroethylene portionand a structural support material portion are bonded together into acomposite, a surface of the polytetrafluoroethylene portion (article) isetched to generate residual fluoroethylenic free radical moieties inpolytetrafluoroethylene polymeric chains of the surface. This isachieved In one embodiment, by chemical etching, and, in anotherembodiment, the etching is achieved with a beam bombardment approach. Inthe case of chemical etching, sodium-ammonia solution etching orsodium-naphthalene solution etching is used. In the case of beambombardment, any of plasma bombardment etching, electron-beam etching,and laser etching is used.

In beam bombardment embodiments, any of a plasma beam, an electron-beam(the preferable source of irradiation), or a laser beam is generated andthen applied to the PTFE surface with sufficient energy for dislodging aplurality of fluoride atoms from the polytetrafluoroethylene of thesurface so that residual fluoroethylenic free radical moieties aregenerated in polytetrafluoroethylene polymeric chains of the surface.

After the surface is etched, an embodiment of an aqueous admixture asdescribed above is saturatively distributed onto the etched surface.Saturative distribution of the aqueous admixture involves both coatingthe aqueous admixture on the general etched surface and then, veryimportantly, providing conditions to enable the aqueous admixture tocomprehensively penetrate to achieve contact with the available bonds ofthe residual fluoroethylenic free radical moieties generated by theetching. In this regard, the aqueous admixture, In one embodiment, isheated; in another embodiment, the aqueous admixture is pressurizedagainst the etched surface; in yet another embodiment, the aqueousadmixture is pressurized against the etched surface and also heated.

In one embodiment, the aqueous admixture is coated on the etched surfaceto provide an aqueous admixture coating having from about 0.0005 toabout 0.01 inches thickness (preferably from about 0.0005 to about 0.005inches thickness). The aqueous admixture coating is then pressurizedagainst the etched surface (In one embodiment, by “squeezing” theaqueous admixture between the PTFE surface and the structural supportmaterial portion) for at least 3 minutes at from about 0.5 to about 10pounds per square inch pressure and from about 25 to about 100 degreesCelsius temperature.

In one embodiment, the water in the aqueous admixture is diminished as aresult of heat and pressure application over time in the saturativedistribution operation. In an alternative embodiment a process such asvacuum evaporation is used to diminish water after the saturativedistribution operation. The water is decreased in all embodiments to alevel of not more than 1 weight percent in the aqueous admixturecoating.

If the structural support material portion has not yet been positionedagainst the residual dewatered aqueous admixture, it is now sopositioned. In this regard, the structural support material article ispositioned against the (residual, if dewatered) aqueous admixture on theetched surface so that the aqueous admixture fluidly fills the interfacebetween the structural support material article and the etched surface.

The residual dewatered aqueous admixture (aqueous admixture with notmore than 1 weight percent water) coating is then cured. In this regard,tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymerhas a melting temperature and the etched surface and residual aqueousadmixture on the etched surface are heated to at least that meltingtemperature for a time sufficient for curing the various polymers sothat they bond to both the PTFE portion and the structural supportmaterial portion of the composite.

In one embodiment, cured admixture is achieved by heating under pressuresuch that the etched surface and the residual (dewatered) aqueousadmixture on the etched surface are sustained at temperature of at least190 degrees Celsius and at a pressure of at least 75 pounds per squareinch for a time period of at least 10 minutes.

In alternative embodiments, positioning of the structural supportmaterial portion against the residual dewatered aqueous admixture isachieved by various respective processes. Traditional processes such acalendaring, pultrusion, multilayer extrusion, and co-injection moldingare used in alternative process embodiments to achieve manufacture ofthe desired composite. In the case of calendaring, the positioning anddewatering steps are substantively combined and then pressure andtemperature are further adjusted to effect curing and bonding.

In one embodiment of pultrusion, a PTFE pipe-form is etched and thencoated with the aqueous admixture, the aqueous admixture is saturativelydistributed in a pressure chamber, the water is adjusted (removed) in avacuum distillation, and the PTFE pipe-form with saturativelydistributed and dewatered residual aqueous admixture is propelledthrough a pultrusion die to acquire an outside coating of (polymeric)structural support material which is then cured along with the curing ofthe admixture.

In one embodiment of co-injection molding, a PTFE article is coated withthe aqueous admixture, the aqueous admixture is saturatively distributedin a pressure chamber, the water is adjusted (removed) in a vacuumdistillation, and the PTFE article with saturatively distributed anddewatered residual aqueous admixture is placed into an injection mold.Structural support material is then injected against the residualaqueous admixture and held under pressure until both it and the residualaqueous admixture have cured.

One application of compositional and method embodiments described hereinis for making a sealant article such as seal for a rotating shaft. Inone embodiment, an admixture with inter-bonded molecules according toFormula I is used for the material of the shaft. In an alternativeembodiment, a composite with inter-bonded molecules according to any ofFormula IV and Formula V is used for the material of the shaft. In yetanother embodiment, a composite of PTFE and Hytrel™ polyester are joinedinto a composite with an oxygen-radical-containing copolymer solution asdescribed herein, and a contact surface for contacting the shaft indynamic rotation is machined into the PIFE portion of the composite. Inoperation of the latter embodiment, the Hytrel™ polyester structurallystabilizes the composite as the PTFE shaft contact surface lightly bearsagainst the rotating shaft.

A second application of compositional and method embodiments describedherein is for making a laminate diaphragm sealant article for adiaphragm pump. In one embodiment, an admixture with inter-bondedmolecules according to Formula I is used for the diaphragm. In analternative embodiment, a flexible composite with inter-bonded moleculesaccording to any of Formula IV and Formula V is used for the diaphragm.In yet another embodiment, a composite of robust laminar sheet is bondedto a PTFE sheet with an oxygen-radical-containing copolymer solution asdescribed herein. In operation of the latter embodiment, thepolytetrafluoroethylene article provides a contact surface forinterfacing to fluid pumped by the pump, and the robust laminar sheetprovides dimensional strength to protect the PTFE sheet from stretchingor tearing.

Yet other applications (article embodiments) are for other packingsealant articles such as gaskets, dynamic seals, static seals, o-rings,co-extruded hose, and items having a sealant article such as a hose forhandling chemicals or fuels where the inner layer of the hose has thechemical resistance properties of a PTFE “lining”. Other application(article) embodiments include encoders and co-extruded fuel hose.

In one embodiment of making any of these or other articles, an articleis made by admixing an elastomer and thermoplastic blend as previouslydescribed, forming the admixed composition into a shaped item for thedesired article; and irradiating the shaped item to cross-link thevarious continuous and dispersed phases or to generate the new moleculessuch as described in any of Formula I, Formula II, and Formula III.

In still another embodiment, where an admixture composition such as aTPV or TPE is acquired for use, an article is made by forming a shapeditem for said article from the elastomer and thermoplastic admixturecomposition and irradiating the shaped item to crosslink the variouscontinuous and dispersed phases or to generate the new molecules such asdescribed in any of Formula I, Formula II, and Formula III.

EXAMPLES

In a first set of Examples, a mixture oftetrafluoroethylene/hexafluoropropylene/vinylidene fluoride emulsion(Dyneon tetrafluoroethylene/hexafluoropropylene/vinylidenefluoride-340C) in aqueous base and epoxy-based aqueous silane solutionis formulated to evaluate bonding of etched PTFE and Hytrel type TPE(2022HS grade, polyester-based TPE from DuPont) samples. The epoxy-basedaqueous silane solution is prepared by combining epoxy resin (Vantico™GT grades from Ciba) and polyethylene oxide (PEO) modified siliconecopolymer as a coupling agent for the silicone to the epoxy. The 50/50(on a weight basis) mixture oftetrafluoroethylene/hexafluoropropylene/vinylidene fluoride emulsion andepoxy-based silicone solution is applied both to a surface of etchedPTFE and to a surface of a Hytrel sample. Eight samples of etched PTFEspecimens independently etched either by chemical means (sodium ammoniaand sodium naphthalene) or by physical mean (plasma) on the bondingsurface of PTFE are prepared.

Application of wet adhesive is controlled to provide a total (wet)adhesive layer thickness of about 1.5 mils between the etched PTFE andHytrel™ surfaces after they are combined into a composite sample.

Each (composite) PTFE-adhesive-TPE sample is placed in a 60 degrees C.oven with a 5 lb weight on top of the combined part for 5 minutes sothat (1) the adhesive layer dries with the PTFE and Hytrel™ parts inposition for the composite, and (2) the adhesive layer is uniformlydistributed along the contours of the interfacing sample surfaces. Eachcomposite sample is then placed between two heated plates, set at 188degrees C., in a hydraulic press. A constant pressure of 75 psi isapplied to the composite part. The residence time in the press is about10 minutes.

Adhesion strength is tested manually using a “hand pull”. The testresults are summarized in Table 1. In interpreting the results of Table1, a “Weak Bond” identifies a result where the composite separates atits interface in response to a relatively low impulse force against thebond; a “Partial Bond” identifies a result where the composite is robustunder a steadily increased pull, but the composite separates when astrong acute impulse is exerted against the bond; a “Strong Bond”identifies a result where the composite is robust under both a steadilyincreased pull and a strong acute impulse. It is also to be noted thatSample A is a benchmark sample etched for a relatively brief timerespective to the potential range of times normally used for sodiumnaphthalene etching of PTFE. TABLE 1 Sample Etching Type Etching MediumResults A Chemical Etch Sodium Partial Bond Naphthalene B Chemical EtchSodium Ammonia Partial Bond C Chemical Etch Sodium Ammonia Weak Bond DChemical Etch Sodium Ammonia Partial Bond E Chemical Etch Sodium AmmoniaStrong Bond F Chemical Etch Sodium Ammonia Partial Bond G Chemical EtchSodium Ammonia Partial Bond H Physical Etch Plasma Beam Weak to PartialBond

Generally speaking, this adhesive formulation shows effectiveness inbonding sodium ammonia etched PTFE to Hytrel™ type TPE.

In a second set of Examples, shaft seal wafers are injection molded in ashaft seal mold using fluoroelastomer thermoplastic vulcanizate(FKM-TPV) materials. Two FKM-TPV formulations are used: one without awear package and the other with a wear package. The molded shaft sealwafers are then clamped between two metal shaft-housing cases. Thecenter portion of each of the seal wafers is trimmed, each seal wafer isplaced into its respective test shaft, and the wafers are thenheat-treated to release residual stresses frozen into their polymericmatrices during the injection molding process. Heat treatment is thenexecuted on the test seal wafers for 4 hours in the oven at 150° C.Selected heat-treated seals are then exposed to electron beam radiationat 6 and 18 MeRAD dosages. A seal durability test is then executed oneach prepared seal using a shaft seal wear tester operating at 2,500 RPMand at 135 degrees Celsius with gear oil (SAE 75W-90) in the oilreservoir. The durability performance of each seal is measured as thetotal running hours until an oil leak occurs through the seal on thewear tester shaft. Table 2 shows performance data for six seals at threedifferent amounts of radiation, with formulation 150A not benefitingfrom the wear package being admixed into its polymeric formulation andwith formulation 150AA benefiting from the wear package being admixedinto its polymeric formulation. TABLE 2 150A 150AA Formulation/Dosage(hours to failure) (hours to failure) 0 MeRAD 140 264 6 MeRAD 363 621 18MeRAD  450 380

As shown in Table 2, the hours-to-failure generally improve when thesample wafers are irradiated with a dosage of electron beam radiationbelow 18 MeRAD.

Compression set data at room temperature is shown for the samples inTable 3. TABLE 3 150A 150AA (Room temperature (Room temperatureFormulation/Dosage compression set values) compression set values) 0MeRAD 45 47 6 MeRAD 34 37 18 MeRAD  29 31

As shown in Table 3, the compression set values of the formulationsconsistently improve when the sample wafers are irradiated with a dosageof electron beam radiation below 18 MeRAD.

Compression set data at a temperature of 150 degrees Celsius is shownfor the samples in Table 4. TABLE 4 150A 150AA (150 degrees Celsius (150degrees Celsius Formulation/Dosage compression set values) compressionset values) 0 MeRAD 72 69 6 MeRAD 53 57 18 MeRAD  53 57

As shown in Table 4, the compression set values of the formulationsconsistently improve when the sample wafers are irradiated with a dosageof electron beam radiation below 18 MeRAD.

The examples and other embodiments described herein are exemplary andnot intended to be limiting in describing the full scope of compositionsand methods of this invention. Equivalent changes, modifications andvariations of specific embodiments, materials, compositions and methodsmay be made within the scope of the present invention, withsubstantially similar results.

1. A method for etching an article made of halogenated polymer,comprising: (a) etching a surface of said article with an electron beam;and (b) placing said surface in an inert environment at a predeterminedtemperature; wherein said electron beam energizes said surface withsufficient energy for dislodging a plurality of halogen atoms from saidhalogenated polymer of said surface and for generating thereby a set ofinitial residual free radical sites in polymeric chains of said surfaceupon conclusion of said etching, and said inert environment and saidpredetermined temperature are sufficient for sustaining at least 99percent of said free radical sites of said set of initial residual freeradical sites for at least 4 hours.
 2. A method according to claim 1wherein said inert environment and said predetermined temperature aresufficient for sustaining at least 90 percent of said free radical sitesof said set of initial residual free radical sites for at least 8 hours.3. A method according to claim 1 wherein said inert environmentcomprises a noble gas.
 4. A method according to claim 1 wherein saidinert environment comprises a noble gas at a pressure of less than 0.1atmospheres.
 5. A method according to claim 1 wherein said inertenvironment comprises any of nitrogen, an applied vacuum, and a spacefree of electrical static.
 6. A method according to claim 1 wherein saidinert environment comprises nitrogen at a pressure of less than 0.1atmospheres.
 7. A method according to claim 1 wherein said generatinggenerates electron beam radiation of from about 0.1 MeRAD to about 40MeRAD.
 8. A method according to claim 1 wherein said generatinggenerates electron beam radiation from about 5 MeRAD to about 20 MeRAD.9.-17. (canceled)